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N. H. GILMORE. HOISTING MPARATUS.

N0. 499,5a6. Patented Jungla, 1893.

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UNITED STATES PATENT OFFICE.

NOBLE H. GILMORE, OF GREENVILLE, MICHIGAN, ASSIGNOR OF THREE- FOURTHS TO JOSEPH M. FULLER, CHARLES S. FULLER, AND WILLIAM H.

GILMORE, OF SAME PLACE.

HOISTI NG APPARATUS.

SPECIFICATION forming part of Letters Patent No. 499,536, dated J' une 13, 1893.

Application iiled November 25, 1892. Serial No. 453,156. (No model.)

To all whom it may concern:

Be it known that I, NOBLE H. GILMoRE, of'` Greenville, in the county of Montcalm and State of Michigan, have invented a new and useful Improvement in Hoisting Apparatus, of which the following is a specification.

My invention pertains to an arrangement of draft-equalizing pulleys below and as an attachment of the upper pulley-block of a compound pulley system, as hereinafter described.

In the accompanying drawings, Figure 1 is a face view of my improved pulley system. Fig 2 is an edge view of the upper pulley-block and the equalizing attachment. Fig. 3 isa cross section on line 3-3 of Fig. l.

My pulley-block system is composed of three parts, or elements, namely, upper and lower multiple-sheave pulley blocks A and B, which are 0f a well-known type, the equalizing pulleys O, which are suspended from the upper block A, and a chain D, which runs on the several sheaves of the system, as will be presently described. Each pulley block A and B, has a series of grooved sheaves journaled side by side, on a through pin, and arranged between parallel plates, a, which form part of the frame of the block. The chain D-indicated by dotted lines Fig. l-passes over the equalizing pulleys C, thence downward and under the respective outer sheaves l, 1, of the lower block B, next upward over the corresponding outer sheaves l l', of the upper block A, then down and over the second set of sheaves 2, 2, of the lower block B, and next over the corresponding sheaves 2' 2', of the upper block A, and then over sheaves 3, 3 and 3' 3', the end portions c c of said chain passing finally over the central and adjacent sheaves 4, 4, of the lower block B. It will be noted that the sheaves C, are journaled in a frame which is permanently attached to the frame of pulley block A, and that said sheaves are also arranged with their parallel axes in planes at a right angle to the axes of the sheaves of block A. It is apparent that if the system be properly suspended from a suitable support, and tension be applied to either or both ends of the chain, it will'cause the latter to travel through the blocks A, B, and over the sheaves C, and thus raise lower block B. And conversely, if tension be relaxed, the chain D, will travel in the reverse direction, and thus lower the said block B. In practical operation, the sheaves of two such pulley blocks A, B seldom work with exact uniformity, and the same may be said of the chain. This may be due to one or more of several causes; for instance, to unequal friction of the several sheaves, or to twisting of the chain, or the application of the hoisting strain in a direction more or less inclined to the vertical. The provision and arrangement of the sheaves C prevent such result, since they allow the middle portion of the chain to travel freely between the extremities of the lower block B, 'L'. e. between the outer sheaves of such block, so that it readily adjusts itself to the proper relative position, or, in other words, maintains a practically parallel position to the upperblock A. Thus the greater friction, draft, and wear, that are incident to the ordinary construction of compound pulley systms of this type, are avolded by a most simple and inexpensive means.

In a compound-pulley system,tl1e combination, with the lower pulley block, B, and the two series of sheaves l', 2', 3' dac., arranged side by side on the saine axis in the upper block, A, of the two equalizing pulleys, C and C, arranged on separate but parallel axes at right angles to the first mentioned axis and located directly beneath the outer ones (1 1') of the said series of upper sheaves, (l, 2', 3 &c.,) and the chain, D, arranged as shown, whereby it passes directly from one equalizing pulley (C) to the other, and thence down to the end sheaves of the lower series (l, 2, 3 dac.) as shown and described, for the purpose specified.

NOBLE H. GILMORE.

Witnesses:

C. S. FULLER, C. L. RAEDEN. 

